Is there asbestos in your house?

If you want to cause homeowner anxiety, there's no better word to do it than "asbestos." Implicated in 5,000 U.S. deaths annually, it's nearly ubiquitous in its presence, yet little understood in its threat.

Here's a primer on what homeowners need to know.

Q: What is asbestos and how common is it?

A: Asbestos is a naturally occurring mineral fiber that's found in the Cascade Mountains, among many other places worldwide. Because asbestos fibers are strong, flexible, heat-resistant and very durable, the mineral has been used in more than 3,000 products. Among them are vehicle brake shoes, cigarette filters — and even school ceilings and floors. As a result, some experts speculate that nearly every adult may have inhaled some asbestos at some time. Much smaller than human hairs, asbestos fibers are essentially invisible.

Q: Why should people be concerned about asbestos?

A: A known carcinogen, it's deadly when inhaled. Those whose work brought them in repeated contact with asbestos fibers (as well as their family members) make up the bulk of cases. Moreover, different types of asbestos have different risks. But there's no known safe level of asbestos exposure, and lung or chest cancer can occur up to 30 years after it's inhaled. According to the Puget Sound Clean Air Agency, the "uncontrolled disturbance of any asbestos-containing material in any concentration is dangerous to your health."

Q: Isn't asbestos illegal now?

A: No. That's a common misconception. While it's no longer used in some products — toothpaste is one example — asbestos has never been outlawed wholesale in U.S. manufacturing. It's still being included in some construction and other products, including asphalt roofing, and their labels don't always reveal this. Asbestos has also been the subject of numerous investigations, 200,000-plus lawsuits and billions of dollars in claims that have forced 60 companies into bankruptcy.

Q: Is it common to find asbestos in Northwest homes?

A: Absolutely. Asbestos first began to make its way into American homes in the mid-1940s and was still being found in some interior home products into the mid-'90s. Theoretically that means homes built in the early 20th century might not contain it — unless they've been remodeled in some way, which of course, most have been. As a result, Bill Walker, whose firm, Walker Specialty Construction, does a lot of asbestos removal around Puget Sound, estimates that any home built before 1995 probably contains some form of it.

Q: Where might residential asbestos be found?

A: There are roughly two dozen different types of products where asbestos is used — everything from cement siding shingles to furnace ductwork insulation to window putty, according to the Environmental Protection Agency. Add to that textured "popcorn" ceilings, artificial fire logs (the sort found in some gas fireplaces) the backing on sheet vinyl flooring, some roofing and plumbing products. (See cover illustration.)

Q: Where is it most commonly found in Western Washington homes?

A: Major uses are in heating systems, exterior-siding cement shingles and popcorn ceilings. (Note: Not all popcorn ceilings contain asbestos.) Another is sheet vinyl flooring, manufactured prior to 1980, that had a paper backing containing asbestos. "People know about the popcorn and the siding, but less about flooring, and that's one of the most common places it's found," says Jim Nolan, compliance director for the Puget Sound Clean Air Agency, which provides property owners with considerable asbestos information and regulates its removal.

Q: What about Zonolite brand attic insulation containing the type of asbestos fiber called tremolite? (That particularly deadly form of asbestos was found in vermiculite ore mined in Libby, Mont., by W.R. Grace Co. and shipped around the world.)

A: The Zonolite brand is indeed vermiculite that sometimes — but not always — contained tremolite asbestos. It was sold from 1963 to 1984 and installed in about 940,000 American homes, according to an EPA estimate. It looks like small, brownish-silver chips. Nolan says he's never seen asbestos in the vermiculite insulation used in the Puget Sound region. "It's possible we're totally missing it, but if we're missing it, it's very rare." However asbestos-containing vermiculite insulation has been found in the Spokane area, Nolan says.

Q: Is in-home asbestos always dangerous?

A: No. Asbestos is only a health problem when its fibers become airborne, as can happen, for example, if an asbestos-containing popcorn ceiling begins to disintegrate. Additionally, some asbestos products only become hazardous if disturbed — like removing 1950s-'60s era Nicolite paper that was used as an underlayment for cedar shake roofs. Not to be confused with dark roofing felt, Nicolite is white and "basically 100 percent asbestos paper," says Nolan. "It's very dangerous."

Mike Cassidy, owner of Long Services, a commercial-building asbestos removal firm, says released fibers can be dangerous for a long time. "It has a tendency to stay in the air if you disturb it — and disturb it wrong."

Other products don't even become dangerous when they are disturbed. Two examples are manufactured roofing shingles and floor tiles. The asbestos in them is so bound up in the product that it cannot escape.

Q: Do the experts recommend removing all asbestos from homes as a precaution?

A: No. "A lot of people are just totally panicked by it and imagine they can't breathe or they can smell it," says Walker. "Generally I tell them if it's not damaged or offensive to them, the best course is to leave it in place." Adds Nolan, "The good news is asbestos is not going to be a problem for you if it's in good shape and you leave it alone."

Q: When should it be removed?

A: When it's in bad shape or needs to be taken out as part of a home-improvement project or remodel. In some cases it can be repaired or encapsulated instead.

Q: How can homeowners learn if certain parts of their homes have asbestos?

A: They can have it tested. Owners of homes that are going to be demolished must have an asbestos survey performed by a specially trained and certified building inspector. Homeowners doing remodeling or repair jobs may get materials in question tested themselves. There are numerous local firms, listed in the Yellow Pages under Asbestos Consulting and Testing, that do this work. They can provide information on the type of sample needed and the cost involved.

Q: How should asbestos be removed?

A: If it's a single-family residence, homeowners can do the work themselves or hire a state-certified professional asbestos abatement contractor. For duplexes or larger, a professional must do the job. They're listed in the Yellow Pages under Asbestos Abatement.

Q: What do homeowners need to know before beginning a removal?

A: That in King, Snohomish, Pierce and Kitsap counties removing asbestos is strictly regulated by the Puget Sound Clean Air Agency. (Northwest Air Pollution Authority regulates removal in Island, Skagit and Whatcom counties. Olympic Region Clean Air Agency has jurisdiction in Thurston, Jefferson, Grays Harbor, Mason, Pacific and Clallam counties.)

That means anyone who undertakes a removal must get a permit (Puget Sound Clean Air charges $25), and follow both testing and removal procedures mandated by the agency.

Additionally, homeowners who hire contractors must abide by state Department of Labor and Industries requirements regarding asbestos abatement. Go online to www.lni.wa.gov for more information.

Q: In general, what's involved in removing asbestos?

A: Obviously that depends on the product involved and where it's located. Often the asbestos-containing material needs to be thoroughly wetted down before being removed. This is to keep the asbestos fibers from becoming airborne. In a popcorn ceiling removal, for example, this means removing all furniture and covering walls and floors with heavy plastic, then spraying and scraping the ceiling according to Clean Air's directions.

The removed building materials must be disposed of at a site that's authorized to accept asbestos-containing hazardous waste. And the persons doing the work must wear a respirator, disposable coveralls, goggles, disposable gloves and rubber boots, according to Clean Air.

Q: If I decide to hire a contractor, how much might that cost?

A: That depends on the location, size and difficulty of the project. Let's use a popcorn ceiling removal as an example. Because of the cost of protecting the site and disposing of the waste, a ceiling job in a large house might go for $3.50 to $5 a square foot, Walker estimates.

Elizabeth Rhodes: erhodes@seattletimes.com.